CN116157235A - Abrasive article and method of making the same - Google Patents

Abstract

An abrasive article includes a porous substrate having openings extending therethrough between opposed first and second major surfaces. An abrasive coating is disposed on only a portion of the first major surface of the porous substrate. The abrasive coating includes a functional layer disposed on only a portion of the first major surface of the porous substrate, a make coat layer disposed on at least a portion of the functional layer opposite the porous substrate, and abrasive particles. The functional layer and the primer layer each include a chemically crosslinked binder. The functional layer completely blocks a first portion of the openings and does not completely block a second portion of the openings, which allows the abraded dust to pass through the abrasive article. Methods of making abrasive articles are also disclosed.

Description

Abrasive article and method of making the same

Background

The coated abrasive article has an abrasive layer secured to a substrate. The substrate may be porous or non-porous. Examples of coated abrasive disks include sandpaper, abrasive disks, and abrasive tape.

It is common that dry sanding operations generate a significant amount of airborne dust. To minimize this airborne dust, it is known to use a porous abrasive article on the tool while a vacuum is drawn through the abrasive article from the abrasive side through the back of the article and into the dust collection system. For this purpose, many film backed abrasive disks are available with added perforations to facilitate vacuum cleaning.

As an alternative to converting dust removal holes into abrasive discs, there are also commercial products in which an abrasive layer is applied onto a porous knitted fabric having loops integrally formed on one side as part of the porous knitted fabric. These loops are used as part of a hook and loop attachment system for attachment to a power tool.

Disclosure of Invention

There is a continuing need for a new coated abrasive product that provides enhanced cutting and/or life performance while exhibiting excellent dusting.

The present disclosure provides a combination of benefits (dust removal in combination with cutting and/or lifetime) by pattern coating a functional layer on a portion of a major surface of a porous substrate and then disposing an abrasive layer on the patterned functional layer. Thus, the patterned abrasive layer can be designed independently of any pattern present on the porous substrate to balance abrasive performance and dust removal.

In one aspect, the present disclosure provides an abrasive article comprising:

a porous substrate having openings extending therethrough between opposed first and second major surfaces;

an abrasive coating disposed on only a portion of the first major surface of the porous substrate, wherein the abrasive coating comprises:

A functional layer disposed on only a portion of the first major surface of the porous substrate, wherein the functional layer comprises a first chemically cross-linked binder, wherein the functional layer completely blocks a first portion of the openings and does not completely block a second portion of the openings;

a primer layer disposed on at least a portion of the functional layer opposite the porous substrate, wherein the primer layer comprises a second chemically crosslinked binder composition; and

abrasive particles dispersed in or at least partially embedded in the make coat,

wherein the second portion of the opening allows the abraded dust to pass through the abrasive article.

In some embodiments, the abrasive article further comprises one component of a two-piece hook and loop attachment system secured to the porous substrate opposite the functional layer.

In another aspect, the present invention provides a method of making an abrasive article, the method comprising:

providing a porous substrate having openings extending therethrough between opposed first and second major surfaces;

disposing a cross-linkable functional layer precursor on the first major surface of the porous substrate, wherein the cross-linkable functional layer precursor completely blocks a first portion of the openings and does not completely block a second portion of the openings;

Crosslinking the crosslinkable functional layer precursor to provide a crosslinked functional layer;

disposing a curable make layer precursor on at least a portion of the crosslinked functional layer opposite the porous substrate, wherein the curable make layer precursor has abrasive particles dispersed therein;

and at least partially curing the first curable adhesive composition,

wherein the second portion of the opening allows the abraded dust to pass through the abrasive article.

In yet another aspect, the present disclosure provides a method of making an abrasive article, the method comprising:

providing a porous substrate having openings extending therethrough between opposed first and second major surfaces;

disposing a cross-linkable functional layer precursor on the first major surface of the porous substrate, wherein the cross-linkable functional layer precursor completely blocks a first portion of the openings and does not completely block a second portion of the openings;

crosslinking the crosslinkable functional layer precursor to provide a crosslinked functional layer;

disposing a curable primer layer precursor on at least a portion of the crosslinked functional layer opposite the porous substrate;

partially embedding abrasive particles in a curable make layer precursor;

At least partially curing the curable primer layer precursor to provide a primer layer;

disposing a curable size coat precursor over the make coat and at least a portion of the abrasive particles; and

at least partially curing the curable size layer precursor to provide the abrasive article,

wherein the second portion of the opening allows the abraded dust to pass through the abrasive article.

A further understanding of the nature and advantages of the present disclosure will be realized when the particular embodiments and the appended claims are considered.

Drawings

Fig. 1 is a schematic perspective view of an exemplary abrasive article 100 according to the present disclosure.

FIG. 1A is a schematic cross-sectional side view of an abrasive article 100 taken along line 1A-1A.

Fig. 2 is a schematic perspective view of an exemplary abrasive article 100 according to the present disclosure.

FIG. 2A is a schematic cross-sectional side view of an abrasive article 200 taken along line 2A-2A.

Fig. 3 is a 50x optical micrograph of a portion of the non-annular side of the mesh substrate used in example 1.

Fig. 4 is a 50x optical micrograph of a pattern edge portion of a pattern coated side of the patterned coated mesh substrate in example 1.

Fig. 5 is a 50x optical micrograph of a portion of the coated side of the abrasive coated mesh substrate of example 1.

Fig. 6 is a 50x optical micrograph of a portion of the coated side of the abrasive article of example 1.

It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that fall within the scope and spirit of the principles of this disclosure. The figures may not be drawn to scale.

Description

An exemplary embodiment of an abrasive article according to the present disclosure is depicted in fig. 1. Referring now to fig. 1, an exemplary abrasive article 100 has a porous substrate 110 (shown as a web) having opposed first and second major surfaces 112, 114. The first major surface 112 has an abrasive coating 116 disposed on only a portion of the porous substrate according to a predetermined pattern 125.

As shown in fig. 1A, the porous substrate 110 has a first portion 115a of openings that extend through the abrasive article and are completely blocked by the functional layer 118, preventing dust from passing through the openings. For the second portion 115b of the openings, the openings are not completely blocked, allowing dust to pass through the openings. The abrasive coating includes a functional layer 118 and a make layer 130 disposed on the functional layer. The make coat 130 includes abrasive particles 140 dispersed in a crosslinked binder composition 135. An optional top glue layer 150 covers the bottom glue layer 130.

The optional attachment interface layer 160 secured to the second major surface of the porous substrate comprises one half of a two-piece mechanical fastening system, shown as the loop portion of a hook and loop fastening system. The optional attachment interface layer may comprise one half of any two-piece mechanical fastening system including, for example, hook and loop fastening systems and mushroom stem web mechanical fasteners.

An exemplary embodiment of an abrasive article according to the present disclosure is depicted in fig. 2. Referring now to fig. 2, an exemplary abrasive article 200 has a porous substrate 210 having opposed first and second major surfaces 212, 214. The first major surface 212 has an abrasive coating 216 disposed on only a portion of the porous substrate according to a predetermined pattern 225.

As shown in fig. 2A, the porous substrate 210 has a first portion 215a of openings that extend through the abrasive article and are completely blocked by the functional layer 218, thereby preventing dust from passing through the openings. For the second portion 215b of the openings, the openings are not completely blocked, allowing dust to pass through the openings.

The abrasive coating 216 includes a functional layer 218 and a make layer 230 disposed on the functional layer. Abrasive particles 240 are partially embedded in make layer 230. The make coat 250 covers the make coat 230 and the abrasive particles 240. An optional top glue layer 260 covers the glue layer 250.

The optional attachment interface layer 270 secured to the second major surface of the porous substrate comprises one half of a two-piece mechanical fastening system, shown as the loop portion of a hook and loop fastening system.

Exemplary porous substrates include knitted fabrics (e.g., knitted fabrics having a volumetric porosity of at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, or even at least 70%), mesh woven fabrics, woven mesh/screen (e.g., wire mesh or fiberglass mesh), porous nonwoven fabrics, monolithic mesh (e.g., monolithic continuous plastic screen), perforated polymer films, and perforated non-porous (e.g., sealed) fabrics. In some embodiments, the porous substrate may comprise a unitary loop substrate, particularly in the case of a knitted fabric.

The porous fabric substrate may be made of any known fibers, whether natural fibers, synthetic fibers, or blends of natural and synthetic fibers. Examples of useful fibrous materials include fibers or yarns comprising polyesters (e.g., polyethylene terephthalate), polyamides (e.g., hexamethylene adipamide, polycaprolactam), polypropylene, acrylic, cellulose acetate, polyvinylidene chloride-vinyl chloride copolymers, vinyl chloride-acrylonitrile copolymers, graphite, polyimide, silk, cotton, linen, jute, hemp, and/or rayon. Usable fibers may be of natural material or recycled or waste material recovered, for example, from apparel cutting, carpet manufacturing, fiber manufacturing, or textile processing. Useful fibers may be homogenous or be a composite such as bicomponent fibers (e.g., co-spun sheath-core fibers). These fibers may be drawn and crimped, but may also be continuous filaments, such as those formed by an extrusion process.

The porous film substrate may comprise a perforated polymeric film including, for example, polyesters (e.g., polyethylene terephthalate), polyamides (e.g., hexamethylene adipamide, polycaprolactam), polypropylene, acrylic acid, cellulose acetate, polyvinylidene chloride-vinyl chloride copolymer, and/or vinyl chloride-acrylonitrile copolymer. Perforation may be provided by, for example, stamping, needling, knife cutting, laser perforation and cutting as described in U.S. patent nos. 9,168,636 (Wald et al) and 9,138,031 (Wood et al). Perforations may also be provided by application of flame, heat source or pressurized fluid, such as described in U.S. patent application Ser. No. 2016/0009048A1 (Slama et al) and U.S. patent No. 7,037,100 (Strobel et al).

The porous substrate may be rigid, semi-rigid or flexible. The porous substrate has openings extending through its body between two opposing major surfaces. The openings may be perforations or spaces between fiber strands of, for example, a fabric.

The openings in the porous substrate should be of sufficient size, which may be the same or different, so that dust generated during the grinding operation can be vacuum drawn through the openings and away from the surface of the workpiece being ground. In some embodiments, the openings are of sufficient size such that some or all of them allow dust particles having an average diameter of less than or equal to 0.01 millimeters (mm), less than or equal to 0.05mm, less than or equal to 0.1mm, less than or equal to 0.15mm, less than or equal to 0.3mm, less than or equal to 0.5mm, less than or equal to 1mm, or even less than or equal to 2mm to pass through the porous backing.

The porous substrate may have a thickness of at least 0.02mm, at least 0.03mm, at least 0.05mm, at least 0.07mm, or even at least 0.1mm, although this is not required. Likewise, the porous substrate may have a thickness of at most 5mm, at most 4mm, at most 2.5mm, at most 1.5mm, or at most 0.4mm in any combination with the aforementioned lower limit, but this is not required.

Generally, the porous substrate should be strong enough to resist tearing or other damage during the abrading process. The thickness and smoothness of the porous substrate should also be suitable to provide the desired thickness and smoothness of the abrasive article; for example, depending on the intended application or use of the abrasive article.

The porous substrate may have any basis weight; for example, in the range of 25 grams per square meter (gsm) to 1000gsm, more typically in the range of 50gsm to 600gsm, and even more typically in the range of 100gsm to 300 gsm. To facilitate adhesion of the functional layer to the porous substrate, one or more surfaces of the porous substrate may be modified by known methods including corona discharge, ultraviolet light irradiation, electron beam irradiation, flame discharge, and/or roughening.

The functional layer is disposed on only a portion of the first major surface of the porous substrate, thereby also allowing some of the openings in the porous substrate to pass dust through the abrasive article during abrading. The functional layer includes a crosslinked binder, which is typically provided by curing a corresponding functional layer precursor including a curable (i.e., chemically crosslinkable) resin. Useful binder precursors include thermally curable resins, moisture curable resins, and radiation curable resins, which can be cured, for example, by exposure to heat, moisture, and/or particulate or electromagnetic radiation. Sources of particulates and electromagnetic radiation can include electron beams (e-beam) and ultraviolet and/or visible light.

Examples of suitable curable resins that may be used in the functional layer precursor include, for example, phenolic resins, urea-formaldehyde resins, aminoplast resins, urethane resins, melamine formaldehyde resins, cyanate ester resins, isocyanurate resins, (meth) acrylate resins (e.g., a (meth) acrylate modified polyurethane, (meth) acrylate modified epoxy resins, ethylenically unsaturated free radical polymerizable compounds, aminoplast derivatives having a, β -unsaturated carbonyl side groups, isocyanurate derivatives having at least one acrylate side group, and isocyanate derivatives having at least one acrylate side group), vinyl ethers, epoxy resins, and combinations thereof. As used herein, the term "(meth) acryl" encompasses acryl or methacryl. Among them, in some embodiments, radiation curable resins are preferred.

Phenolic resins have good thermal properties, availability and relatively low cost, and are easy to handle. Phenolic resins are of two types: resole resins and novolac resins. The molar ratio of formaldehyde to phenol in the resole resin is greater than or equal to 1:1, typically in the range of 1.5:1.0 to 3.0:1.0. The molar ratio of formaldehyde to phenol in the novolac resin is less than 1:1. Examples of commercially available phenolic resins include those known under the trade names: DUREZ and varum, available from western chemical company of Dallas, texas (Occidental Chemicals corp., dallas, texas); RESINOX, available from mendo corporation (Monsanto co., saint Louis, missouri); and AEROFENE and AROTAP from ashland specialty chemicals company (Ashland Specialty Chemical co., dublin, ohio) of Dublin, duhio.

The (meth) acrylated urethanes include di (meth) acrylates of hydroxyl terminated NCO extended polyesters or polyethers. Examples of commercially available acrylated urethanes include those available from Cytec Industries, west Paterson, N.J., from Cytec Industries, inc. as CMD 6600, CMD 8400, and CMD 8805.

The (meth) acrylated epoxy resin includes di (meth) acrylates of epoxy resins, such as the diacrylates of bisphenol a epoxy resins. Examples of commercially available acrylated epoxies include those available from Cytec Industries as CMD 3500, CMD 3600, and CMD 3700.

Ethylenically unsaturated free-radically polymerizable compounds include monomeric and polymeric compounds that include carbon atoms, hydrogen atoms, and oxygen atoms, and optionally nitrogen and halogens. Oxygen or nitrogen atoms or both are typically present in ether, ester, polyurethane, amide and urea groups. Ethylenically unsaturated free radical polymerizable compounds typically have a molecular weight of less than about 4,000 g/mole and are typically esters made from the reaction of compounds containing a single aliphatic hydroxyl group or multiple aliphatic hydroxyl groups with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, and the like. Representative examples of (meth) acrylate resins include methyl methacrylate, ethyl methacrylate styrene, divinylbenzene, vinyl toluene, ethylene glycol diacrylate, ethylene glycol methacrylate, hexanediol diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, glycerol triacrylate, pentaerythritol methacrylate, pentaerythritol tetraacrylate, and pentaerythritol tetrastearate. Other ethylenically unsaturated resins include monoallyl, polypropylene and polymethylallyl esters and carboxylic acid amides, such as diallyl phthalate, diallyl adipate and N, N-diallyl adipamide. While other nitrogen-containing compounds include tris (2-propenoyl-oxyethyl) isocyanurate, 1,3, 5-tris (2-methacryloyloxyethyl) s-triazine, acrylamide, N-methacrylamide, N-dimethylacrylamide, N-vinylpyrrolidone and N-vinylpiperidone.

Useful aminoplast resins have at least one α, β -unsaturated carbonyl side group per molecule or per oligomer. These unsaturated carbonyl groups may be acrylate, methacrylate or acrylamide type groups. Examples of such materials include N-methylol acrylamide, N' -oxydimethylene bisacrylamide, ortho-and para-acrylamidomethylated phenol, acrylamide methylated novolac resins, and combinations thereof. These materials are further described in U.S. patent nos. 4903440 and 5236472 (both to Kirk et al).

Isocyanurate derivatives having at least one acrylate-side group and isocyanate derivatives having at least one acrylate-side group are further described in U.S. Pat. No. 4,652,274 (Boettcher et al). An example of an isocyanurate material is the triacrylate of tris (hydroxyethyl) isocyanurate.

The epoxy resin has one or more epoxy groups and can be polymerized by ring-opening reaction of the epoxy groups. Such epoxy resins include monomeric epoxy resins and oligomeric epoxy resins. Examples of useful epoxy resins include: 2, 2-bis [4- (2, 3-epoxypropoxy) -phenylpropane ] (diglycidyl ether of bisphenol) and hansen (Hexion inc., houston, texas) available as EPON 828, EPON 1004 and EPON 1001F; and materials available as DER-331, DER-332, and DER-334 from Dow Chemical Co., midland, mich. Other suitable epoxy resins include glycidyl ethers of novolac resins commercially available as DEN-431 and DEN-428 from Dow Chemical Co.

The epoxy resin may be polymerized by a cationic mechanism with the addition of a suitable cationic curative. The cationic curing agent generates an acid source to initiate polymerization of the epoxy resin. These cationic curing agents may include salts with onium cations and halogens comprising complex anions of metals or metalloids. Other curing agents for epoxy and phenolic resins (e.g., amine hardeners and guanidine) may also be used.

Other cationic curing agents include salts with organometallic complex cations and halogens containing complex anions of metals or metalloids, which are further described in U.S. patent No. 4751138 (Tumey et al). Another example are organometallic salts and onium salts, which are described in U.S. Pat. No. 4,985,340 (Palazzotto et al), 5,086,086 (Brown-Wensley et al) and 5,376,428 (Palazzotto et al). Other cationic curing agents include ionic salts of organometallic complexes wherein the metal is selected from the group consisting of IVB, VB, VIB, VIIB and VIIIB elements of the periodic Table of the elements described in U.S. Pat. No. 5385954 (Palazzotto et al).

Examples of the radical thermal initiator include peroxides, for example, benzoyl peroxide and azo compounds.

When exposed to actinic electromagnetic radiation, the compounds that generate the free radical source are commonly referred to as photoinitiators. Examples of photoinitiators include benzoin and derivatives thereof such as alpha-methyl benzoin; alpha-phenylbenzoin; alpha-allyl benzoin; alpha-benzyl benzoin; benzoin ethers such as benzoin dimethyl ketal (commercially available as IRGACURE 651 from BASF, ludwigshafen, germany) benzoin methyl ether, benzoin ethyl ether, benzoin n-butyl ether; acetophenone and derivatives thereof, such as 2-hydroxy-2-methyl-1-phenyl-1-propanone (available from BASF) as DAROCUR 1173) and 1-hydroxycyclohexyl phenyl ketone (available from BASF) as IRGACURE 184; 2-methyl-1- [4- (methylsulfanyl) phenyl ] -2- (4-morpholinyl) -1-propanone (e.g., available as IRGACURE 907 from BASF) corporation; 2-benzyl-2- (dimethylamino) -1- [4- (4-morpholinyl) phenyl ] -1-butanone (e.g., available as IRGACURE 369 from Basf). Other useful photoinitiators include, for example: pivaloin (pivaloin) ether, anisoin ether, anthraquinones (e.g., anthraquinone, 2-ethylanthraquinone, 1-chloroanthraquinone, 1, 4-dimethylanthraquinone, 1-methoxyanthraquinone, or benzanthraquinone), halomethyltriazine, benzophenone and derivatives thereof, iodonium salts and sulfonium salts, titanium complexes such as bis (η5-2, 4-cyclopentadien-1-yl) -bis [2, 6-difluoro-3- (1H-pyrrol-1-yl) phenyl ] titanium (e.g., available as CGI 784DC from BASF); halomethylnitrobenzene (e.g., 4-bromomethylnitrobenzene), monoacylphosphines, and bisacylphosphines (e.g., as IRGACURE 1700, IRGACURE 1800, IRGACURE 1850, and DAROCUR 4265 all available from BASF). Combinations of photoinitiators may be used. One or more spectral sensitizers (e.g., dyes) may be used with the photoinitiator, e.g., to increase the sensitivity of the photoinitiator to a particular source of actinic radiation.

To ensure crosslinking/curing of the curable resin, it should generally comprise at least one polymerizable monomer having at least 2, at least 3, or even at least 4 polymerizable groups, although post-treatment (e.g., with ionizing radiation) may also be effective to cause crosslinking.

The foregoing curable resins may be combined with one or more of catalysts, initiators (e.g., free radical thermal initiators or free radical photoinitiators), synergists, sensitizers, fillers, coupling agents, colorants, or antioxidants. The amount and choice of any catalyst and/or initiator will vary depending on the curable resin selected and is within the ability of one of ordinary skill in the art. Generally, an amount of less than or equal to 10 wt%, preferably 5 wt% or less is sufficient to effect curing of the curable resin to an extent sufficient to provide a functional layer.

Thermal curing may be achieved by heating or exposure to radio frequency or infrared radiation, while photo-curing may be achieved, for example, by exposure to actinic radiation (e.g., visible and/or ultraviolet electromagnetic radiation).

The functional layer and functional layer precursor may be modified by various additives including, for example: surfactants (e.g., defoamers such as ethoxylated nonionic surfactants such as DYNOL 604), pigments (e.g., carbon BLACK pigments such as C-ser BLACK 7LCD 4115), fillers (e.g., silica such as CABOSIL M5), synthetic waxes (e.g., synthetic paraffin MP 22), stabilizers, plasticizers, tackifiers, flow control agents, cure rate retarders, adhesion promoters (e.g., silanes such as (3-glycidoxypropyl) trimethoxysilane (GPTMS) and titanates), adjuvants, impact modifiers, rheology modifiers, expanded microspheres, thermally conductive particles, electrically conductive particles, fillers such as silica, glass, clay, talc, colorants, glass beads and/or bubbles, and antioxidants.

The functional layer may be prepared by pattern coating a functional layer precursor onto a porous substrate and then curing it. Useful patterned coating methods may include, for example, gravure roll coating, spray coating, flexographic printing, jet printing, stencil printing, slot coating, and ink jet printing. Alternatively, the functional layer may be prepared by: the functional layer precursor is pattern coated onto the release liner, covered with the porous substrate, the precursor is at least partially cured, and then the release liner is removed.

Preferably, the functional layer precursor is sufficiently viscous during the pattern coating process that it can block the openings it coats without significant penetration, at least until it is cured. However, lower viscosity formulations that permeate the openings and thereby clog them can also be used.

In some embodiments, the functional layer may have a thickness of 5 microns to 200 microns, preferably 20 microns to 200 microns; however, this is not necessary.

The functional layers may be disposed on the porous substrate randomly or according to a predetermined pattern (e.g., dots, grids, stripes, and/or wavy stripes). The pattern may be contiguous or non-contiguous.

A primer layer comprising a crosslinked polymeric material is disposed on at least a portion, preferably at least substantially all, of the functional layer opposite the porous substrate.

In the embodiment shown in fig. 1 and 1A, the abrasive particles are dispersed throughout the make coat. In the embodiment shown in fig. 2 and 2A, the abrasive particles are partially embedded in the make coat.

The primer layer comprises a first crosslinked adhesive composition and is typically prepared by at least partially curing a curable primer layer precursor, which may be the same or different from the functional layer precursor.

In a preferred embodiment, the primer layer precursor comprises a phenolic resin (e.g., PREFERRED 80 5077A available from Arclin, mississauga, ontario, canada, inc. of Mississage, ontario). Suitable phenolic resins are typically formed by the condensation of phenol or alkylated phenols (e.g., cresols) and formaldehyde and are generally classified as resoles or novolac resins. The novolac phenolic resin is acid catalyzed and the molar ratio of formaldehyde to phenol is less than 1:1. Resole/resole phenolic resins may be catalyzed with basic catalysts and the molar ratio of formaldehyde to phenol is greater than or equal to one, typically between 1.0 and 3.0, so that pendant hydroxymethyl groups are present. Basic catalysts suitable for catalyzing the reaction between the aldehyde and phenol components of the resole resin include sodium hydroxide, barium hydroxide, potassium hydroxide, calcium hydroxide, organic amines, and sodium carbonate, all of which act as catalyst solutions dissolved in water.

Resoles are typically coated as solutions with water and/or organic solvents (e.g., alcohols). Typically, the solution contains solids in an amount of about 70 wt% to about 85 wt%, although other concentrations may be used. If the solids content is very low, more energy is required to remove the water and/or solvent. If the solids content is very high, the viscosity of the resulting phenolic resin is too high, which often leads to processing problems.

Phenolic resins are well known and readily available from commercial sources. Examples of commercially available resoles useful in the practice of the present disclosure include those sold by Du Leici company (Durez Corporation) under the trade names varum (e.g., 29217, 29306, 29318, 29338, 29353); those sold under the trade name AEROFENE (e.g., AEROFENE 295) by a Shi Lande Chemical company of barton, florida (Ashland Chemical co., barnow, florida); and those sold under the trade name PHENOLITE (e.g., PHENOLITE TD-2207) by Jiangnan chemical Co., ltd (Kangnam Chemical Company Ltd. Of Seoul, south Korea) of Korea.

The primer layer precursor may include additional components including polyurethane dispersions such as aliphatic and/or aromatic polyurethane dispersions. For example, the polyurethane dispersion may comprise a polycarbonate polyurethane, a polyester polyurethane, or a polyether polyurethane. The polyurethane may comprise a homopolymer or a copolymer.

Examples of commercially available polyurethane dispersions include aqueous aliphatic polyurethane emulsions available as NEOREZ R-960, NEOREZ R-966, NEOREZ R-967, NEOREZ R-9036 and NEOREZ R-9699 from Di SiMannich resin company of Wilmington, mass. (DSM Neo Resins, inc., wilmington, massachusetts); aqueous anionic polyurethane dispersions available as ESSENTIAL CC4520, ESSENTIAL CC4560, ESSENTIAL R4100 and ESSENTIAL R4188 from basic industries of mercton, weisconsin (Essential Industries, inc., merton, wisconsin); polyester polyurethane dispersions available as sance 843, sance 898, and sance 12929 from Lubrizol, inc (Cleveland, ohio); aqueous aliphatic self-crosslinking polyurethane dispersions available as TURBOSET 2025 from Lubrizol, inc.; cosolvent-free aqueous anionic aliphatic self-crosslinking polyurethane dispersions available under the trade name BAYHYDROL PR240 from Pittsburgh Bayer materials science, inc. (Bayer Material Science, LLC (Pennsylvania)) of Pa.

Additional suitable commercially available aqueous polyurethane dispersions include:

1) Alberdingk U6150, a solvent-free aliphatic polycarbonate polyurethane dispersion, available from Eurobodibao Lydel, inc. (Alberdingk Boley GmbH, krefeld, germany) of gram Lei Feier, has a viscosity of 50 mPas-500 mPas (spindle 1/rpm 20/factor 5 according to ISO 1652,Brookfield RVT), an elongation at break of about 200% and a cured Koenig hardness of about 65s-70s;

2) Alberdingk U6800, an aqueous, solvent-free, colloidal low viscosity dispersion of aliphatic polycarbonate polyurethane free of free isocyanate groups, available from Eurobodibao Lyder, inc. (Alberdingk Boley GmbH, krefeld, germany) of Lei Feier Germany, has a viscosity of about 20 mPa.s to 200 mPa.s (spindle 1/rpm 50/factor 2 according to ISO 2555,Brookfield RVT), an elongation at break of about 500% and a Koenig hardness after curing of about 45s;

3) Alberdingk U6100, an aqueous, colloidal, anionic, low viscosity dispersion of aliphatic polyester-polyurethane free of free isocyanate groups, available from Eurobobao Laiden Co., ltd (Alberdingk Boley GmbH, krefeld, germany) of gram Lei Feier, having a viscosity of about 20 mPa.s-200 mPa.s (spindle 1/rpm 50/factor 2 according to ISO 1652,Brookfield RVT), an elongation at break of about 300% and a Koenig hardness after curing of about 50s;

4) Alberdingk U9800, a solvent free aliphatic polyester polyurethane dispersion, available from Eurobodibao Lyard, inc. (Alberdingk Boley GmbH, krefeld, germany) of gram Lei Feier, has a viscosity of about 20 mPas to 200 mPas (spindle 1/rpm 20/factor 5 according to ISO 1652,Brookfield RVT), and an elongation at break of about 20% to 50% and a Koenig hardness after curing of about 100s to 130s; and

5) Adiprene BL 16-liquid polyurethane elastomer with blocked isocyanate cure sites, available from kopoly corporation of Middlebury, connecticut.

Optional additives for polyurethane dispersions and generally for curable compositions (including rheology modifiers, defoamers, water-based latexes, and cross-linking agents) may be added to the aqueous polyurethane dispersion. Suitable crosslinking agents include, for example, polyfunctional aziridines, methoxy methylolated melamine, urea resins, carbodiimides, polyisocyanates and blocked isocyanates. Additional water may also be added to dilute the formulation of the aqueous polyurethane dispersion, phenolic resin, or a combination thereof. The curable composition may be made, for example, from an aqueous polyurethane dispersion and a water-based latex.

The aqueous polyurethane dispersion may comprise less than 20%, less than 10%, less than 5% or less than 2% organic solvent. In particular embodiments, the aqueous polyurethane dispersion is substantially free of organic solvents. In some embodiments, it has been found that the aqueous polyurethane dispersion comprises at least about 7%, 15% or 20% solids, and no greater than about 50% or 60% solids. The aqueous polyurethane dispersion may contain no more than about 80%, 85% or 93% water.

In some embodiments, it has been found that the aqueous polyurethane dispersion forms a film having a Koenig hardness of at least about 30 seconds and not greater than about 200 seconds when measured according to ASTM 4366-16. Furthermore, in some embodiments, it has been found that the surface tension of the aqueous polyurethane dispersion can be at least about 50% and no greater than about 300% of the surface tension of water. And in some embodiments, the aqueous polyurethane dispersion may have a viscosity of at least about 10mPa s to no more than about 600mPa s, or at least about 70%, 80% or 90% of the water viscosity and no more than about 600%, 500% or 400% of the water viscosity.

Further, in some embodiments, the aqueous polyurethane dispersion may comprise at least about 100 parts per million (ppm), 1000ppm, or even at least about 10000ppm dimethylolpropionic acid. For example, optional additives (including rheology modifiers, defoamers, and crosslinkers) may be added to the aqueous polyurethane dispersion. Suitable crosslinking agents include, for example, polyfunctional aziridines, methoxy methylolated melamine, urea resins, carbodiimides, polyisocyanates and blocked isocyanates. Additional water may be added to reduce the viscosity of the aqueous polyurethane dispersion. Likewise, the addition of up to 10 weight percent of an organic solvent (e.g., propyl methyl ether or isopropyl alcohol) to the aqueous polyurethane dispersion may be used to reduce viscosity and/or improve miscibility of the ingredients.

The dispersion polyurethane may comprise at least one polycarbonate segment, but this is not a requirement.

The phenolic resin and aqueous polyurethane dispersion components are mixed in a solid weight ratio of 91 to 99 weight percent phenolic resin to 9 to 1 weight percent polyurethane. In some embodiments, the phenolic resin and the aqueous polyurethane dispersion component are mixed in a solids weight ratio of 56 to 91 weight percent phenolic resin to 44 to 9 weight percent polyurethane. In some embodiments, the phenolic resin and the aqueous polyurethane dispersion component are mixed in a solids weight ratio of 62 to 91 weight percent phenolic resin to 38 to 9 weight percent polyurethane. In some embodiments, the phenolic resin and aqueous polyurethane dispersion components are mixed in a solids weight ratio of 69 to 91 weight percent phenolic resin to 31 to 9 weight percent polyurethane. In some embodiments, the phenolic resin and the aqueous polyurethane dispersion component are mixed in a solids weight ratio of 56 to 83 weight percent phenolic resin to 44 to 17 weight percent polyurethane. In some embodiments, the phenolic resin and the aqueous polyurethane dispersion component are mixed in a solids weight ratio of 56 to 76 weight percent phenolic resin to 44 to 24 weight percent polyurethane. In some embodiments, the phenolic resin and the aqueous polyurethane dispersion component are mixed in a solids weight ratio of 56 to 69 weight percent phenolic resin to 44 to 31 weight percent polyurethane.

In some embodiments of the type shown in fig. 1, the make layer may be a structured abrasive layer comprising a plurality of shaped (e.g., precisely shaped) abrasive composites. In such embodiments, the primer layer preferably comprises a photocurable crosslinked acrylic polymer, although any crosslinked polymeric binder material may be used. Details regarding photocurable acrylic monomers are discussed above. Details regarding the molding and curing steps involved in preparing the structured abrasive composites can be found, for example, in U.S. Pat. No. 5,152,917 (Pieper et al) and U.S. patent application publication No. 2011/0065362A1 (Woo et al).

Useful abrasive particles can be the result of a crushing operation (e.g., crushed abrasive particles that have been classified according to shape and size) or a shaping operation (i.e., shaped abrasive particles) in which an abrasive precursor material is shaped (e.g., molded), dried, and converted to a ceramic material. Combinations of abrasive particles produced by comminution and abrasive particles produced by a forming operation may also be used. The abrasive particles can be in the form of, for example, individual particles, agglomerates, composite particles, and mixtures thereof.

The abrasive particles should have sufficient hardness and surface roughness to function as crushed abrasive particles in the grinding process. Preferably, the abrasive particles have a mohs hardness of at least 4, at least 5, at least 6, at least 7 or even at least 8.

Suitable abrasive particles include, for example, crushed abrasive particles comprising: fused alumina, heat treated alumina, white fused alumina, ceramic alumina materials such as those commercially available as 3M CERAMIC ABRASIVE GRAIN from 3M company of santa paul, minnesota (3M Company,St.Paul,Minnesota), brown alumina, blue alumina, silicon carbide (including green silicon carbide), titanium diboride, boron carbide, tungsten carbide, garnet, titanium carbide, diamond, cubic boron nitride, garnet, fused alumina-zirconia, iron oxide, chromia, zirconia, titania, tin oxide, quartz, feldspar, flint, silicon carbide, sol-gel prepared ceramics (e.g., alpha alumina), and combinations thereof. Examples of sol-gel derived abrasive particles from which the abrasive particles can be isolated and methods of their preparation can be found in U.S. Pat. nos. 4,314,827 (leigheiser et al), 4,623,364 (Cottringer et al), 4,744,802 (Schwabel), 4,770,671 (Monroe et al) and 4,881,951 (Monroe et al). It is also contemplated that the abrasive particles may include abrasive agglomerates, such as those described in U.S. Pat. No. 4,652,275 (Bloecher et al) or 4,799,939 (Bloecher et al), and the like. In some embodiments, the abrasive particles may be surface treated or otherwise physically treated (e.g., iron oxide or titanium oxide) with a coupling agent (e.g., an organosilane coupling agent) to enhance the adhesion of the crushed abrasive particles to the binder. The abrasive particles may be treated prior to their incorporation into the binder, or they may be surface treated in situ by including a coupling agent into the binder.

Preferably, the abrasive particles (and in particular abrasive particles) comprise ceramic abrasive particles, such as, for example, polycrystalline alpha alumina particles prepared by a sol-gel process. The sol-gel alpha alumina particle precursors can be used to prepare ceramic crushed abrasive particles composed of crystallites of alpha alumina, magnesia-alumina spinel, and rare earth hexaaluminates according to methods described, for example, in U.S. patent No. 5,213,591 (Celikkaya et al) and U.S. published patent applications 2009/0165394A1 (Culler et al) and 2009/0169816A1 (Erickson et al). Further details regarding methods of making sol-gel derived abrasive particles can be found in, for example, U.S. Pat. Nos. 4,314,827 (Leitheiser), 5,152,917 (Pieper et Al), 5,435,816 (Spurgeon et Al), 5,672,097 (Hoopman et Al), 5,946,991 (Hoopman et Al), 5,975,987 (Hoopman et Al) and 6,129,540 (Hoopman et Al), and U.S. published patent application 2009/0165394Al (Curler et Al).

In some preferred embodiments, useful abrasive particles (particularly in the case of abrasive particles) can be shaped abrasive particles, which can be found in U.S. Pat. nos. 5,201,916 (Berg), 5,366,523 (rowunhorst (Re 35,570)) and 5,984,988 (Berg). U.S. patent No. 8,034,137 (Erickson et al) describes alumina abrasive particles that have been formed into a specific shape and then crushed to form fragments that retain a portion of their original shape characteristics. In some embodiments, the abrasive particles are precisely shaped (i.e., the shape of the particles is determined at least in part by the shape of the cavities in the production tool used to prepare them). Details on such abrasive particles and methods of making them can be found, for example, in U.S. Pat. nos. 8,142,531 (Adefris et al), 8,142,891 (Culler et al), 8,142,532B2 (Erickson et al), 9,771,504 (Adefris); and U.S. patent application publications 2012/0227333 (Adefris et al), 2013/0040537 (Schwabel et al) and 2013/0125777 (Adefris). One particularly useful precisely-shaped abrasive particle shape is a platelet shape having three sidewalls, any of which may be straight or concave, and which may be perpendicular or inclined relative to the platelet base; for example, as described in the references cited above.

The surface coating on the abrasive particles may be used to improve adhesion between the abrasive particles and the binder material, or to aid in electrostatic deposition of the abrasive particles. In one embodiment, the surface coating described in U.S. Pat. No. 5,352,254 (Celikkaya) can be used in an amount of 0.1% to 2% of the surface coating relative to the weight of the abrasive particles. Such surface coatings are described in U.S. Pat. No. 5,213,591 (Celikkaya et al); 5,011,508 (Wald et al), 1,910,444 (Nicholson), 3,041,156 (Rowse et al), 5,009,675 (Kunz et al), 5,085,671 (Martin et al), 4,997,461 (Markhoff-Matheny et al) and 5,042,991 (Kunz et al). In addition, the surface coating may prevent the shaped abrasive particles from being capped. "capping" is a term describing the phenomenon in which metal particles from the workpiece being abraded are welded to the tops of abrasive particles. Surface coatings that perform the above functions are known to those skilled in the art.

In some embodiments, the length and/or width of the abrasive particles may be selected to be in the range of 0.1 micrometers to 3.5 millimeters (mm), more typically in the range of 0.05mm to 3.0mm, and more typically in the range of 0.1mm to 2.6mm, although other lengths and widths may be used.

Abrasive particles having a thickness in the range of 0.1 microns to 1.6 mm, more typically 1 micron to 1.2 mm, may be selected, although other thicknesses may be used. In some embodiments, the abrasive particles can have an aspect ratio (length to thickness ratio) of at least 2, 3, 4, 5, 6, or more.

Abrasive particles can be individually sized according to an abrasive industry accepted prescribed nominal grade. Exemplary abrasive industry accepted grading standards include those promulgated by ANSI (american national standards institute), FEPA (european union of abrasive manufacturers), and JIS (japanese industrial standard). Such industry accepted grading standards include, for example: ANSI 4, ANSI 6, ANSI 8, ANSI 16, ANSI 24, ANSI 30, ANSI 36, ANSI 40, ANSI 50, ANSI 60, ANSI 80, ANSI 100, ANSI 120, ANSI 150, ANSI 180, ANSI 220, ANSI 240, ANSI 280, ANSI 320, ANSI 360, ANSI 400, and ANSI 600; FEPA P8, FEPA P12, FEPA P16, FEPA P24, FEPA P30, FEPA P36, FEPA P40, FEPA P50, FEPA P60, FEPA P80, FEPA P100, FEPA P120, FEPA P150, FEPA P180, FEPA P220, FEPA P320, FEPA P400, FEPA P500, FEPA P600, FEPA P800, FEPA P1000, FEPA P1200; FEPA F8, FEPA F12, FEPA F16, and FEPA F24; and JIS 8, JIS 12, JIS 16, JIS 24, JIS 36, JIS 46, JIS 54, JIS 60, JIS 80, JIS 100, JIS 150, JIS 180, JIS 220, JIS 240, JIS 280, JIS 320, JIS 360, JIS 400, JIS 600, JIS 800, JIS 1000, JIS 1500, JIS 2500, JIS 4000, JIS 6000, JIS 8000 and JIS 10,000. More typically, the size of the crushed alumina particles and the seeded sol-gel process prepared alumina-based abrasive particles are independently set to ANSI 60 and 80 or FEPA F36, F46, F54 and F60 or FEPA P60 and P80 classification standards.

Alternatively, the abrasive particles may be classified into nominal screening grades using a us standard test screen conforming to astm e-11"Standard Specification for Wire Cloth and Sieves for Testing Purposes (standard specification for screen cloth and screen for testing purposes). ASTM E-11 specifies the design and construction requirements of test sieves that use the media of a steel wire mesh woven screen cloth mounted in a frame to classify materials according to specified particle size. Typical numbers may refer to-18+20, which means that the shaped abrasive particles may pass through a test sieve No. 18 conforming to ASTM E-11 specifications, but may remain on a test sieve No. 20 conforming to ASTM E-11 specifications. In one embodiment, the shaped abrasive particles have a particle size such that: so that most of the particles pass through an 18 mesh test screen and can remain on a 20, 25, 30, 35, 40, 45 or 50 mesh test screen. In various embodiments, the shaped abrasive article can have the following nominal screening grades, including: -18+20, -20+25, -25+30, -30+35, -35+40, -40+45, -45+50, -50+60, -60+70, -70+80, -80+100, -100+120, -120+140, -140+170, -170+200, -200+230, -230+270, -270+325, -325+400, -400+450, -450+500 or-500+635. Alternatively, custom mesh sizes such as-90+100 may be used.

The abrasive particles may optionally be oriented by the influence of a magnetic field before the make coat precursor cures. See, for example, commonly owned PCT publications WO 2018/080703, WO 2018/080756, WO 2018/080704, WO 2018/080705, WO 2018/080765, WO 2018/080784, WO 2018/136271, WO 2018/134732, WO 2018/080755, WO 2018/080799, WO 2018/136269 and WO 2018/136268.

In some embodiments, the abrasive particles can optionally be placed using a tool for controlled orientation and placement of the abrasive particles. See, for example, commonly owned PCT publications WO 2012/112305, WO 2015/100020, WO 2015/100220, WO 2015/100018, WO 2016/028683, WO 2016/089675, WO 2018/063262, WO 2018/063960, WO 2018/063978, WO 2019/102312, WO 2019/102329, WO 2019/102330, WO 2019/102331, WO 2019/102332, WO 2016/205133, WO 2016/205267, WO 2017/007414, WO 2017/0075703, WO 2018/690, WO 2018/201699, WO 2018/118688, U.S. patent publication 2019/0275641, and U.S. provisional patent applications 62/751097, 62/767853, 62/76888, 62/780987, 62/780988, 62/780994, 62/0998, 62/787878787878, 62/787878, 62/78787, 62/787813, 62/781, 62/7813, 62/7862/7878, 62/08232, and 08232/08232, and 0827/08232.

In the embodiment shown in fig. 2 and 2A, a size coat comprising a crosslinked polymeric binder is disposed on at least a portion, preferably at least substantially all, of the size coat opposite the functional layer. While a minimum amount of size coat is allowed to extend beyond the make coat, it is preferred that the size coat reside substantially entirely on the make coat and abrasive particles.

The size layer may be prepared in the same manner from a size layer precursor comprising any of the aforementioned curable materials in the primer layer and/or functional layer, which may be the same or different from the size layer. In a preferred embodiment, the size layer comprises a cured phenolic resin; for example, as described above. The size layer precursor may be applied to the make layer and cured to form the size layer by any suitable technique, including those techniques for applying and curing the make layer precursor and/or functional layer precursor.

The primer layer and size layer, and their precursors, may contain, among other components, optional additives to, for example, modify performance and/or appearance. Exemplary additives include grinding aids, fillers, plasticizers, wetting agents, surfactants, pigments, coupling agents, fibers, lubricants, thixotropic materials, antistatic agents, suspending agents, and/or dyes.

Exemplary grinding aids may be organic or inorganic, including waxes, halogenated organic compounds, such as chlorinated waxes, e.g., naphthalene tetrachloride, naphthalene pentachloride, and polyvinyl chloride; halide salts such as sodium chloride, potassium cryolite, sodium cryolite, ammonium cryolite, potassium tetrafluoroborate, sodium tetrafluoroborate, silicon fluoride, potassium chloride, magnesium chloride; and metals and their alloys, such as tin, lead, bismuth, cobalt, antimony, cadmium, iron, and titanium. Examples of other grinding aids include sulfur, organosulfur compounds, graphite, and metal sulfides. A combination of different grinding aids may be used. Exemplary antistatic agents include conductive materials such as vanadium pentoxide (e.g., dispersed in sulfonated polyester), humectants, carbon black in binders, and/or graphite.

Examples of fillers useful in the present disclosure include silica, such as quartz, glass beads, glass bubbles, and glass fibers; silicates such as talc, clay, (montmorillonite) feldspar, mica, calcium silicate, calcium metasilicate, sodium aluminosilicate, sodium silicate; metal sulfates (such as calcium sulfate, barium sulfate, sodium aluminum sulfate, aluminum sulfate); gypsum; vermiculite; wood powder; aluminum trihydrate; carbon black; alumina; titanium dioxide; cryolite; cone cryolite; and metal sulfites (such as calcium sulfite).

The abrasive article may also optionally include a make layer. Generally, the make layer is the outermost coating of the abrasive article and is in direct contact with the workpiece during the abrading operation. For example, it may be disposed on the size layer, on the primer layer if there is no size layer, and on the uncoated portion of the porous substrate. The optional make coat may be used to prevent or reduce the accumulation of dust (material abraded from the workpiece) between the abrasive particles, which may significantly reduce the cutting ability of the coated abrasive disk. Useful make coats typically include grinding aids (e.g., potassium tetrafluoroborate), metal salts of fatty acids (e.g., zinc stearate or calcium stearate), salts of phosphate esters (e.g., potassium behenyl phosphate), phosphate esters, urea-formaldehyde resins, mineral oils, crosslinked silanes, crosslinked silicones, and/or fluorochemicals. Useful top coat materials are additionally described, for example, in U.S. patent No. 5,556,437 (Lee et al). Typically, the amount of grinding aid incorporated into the coated abrasive article is from about 50gsm to about 400gsm, more typically from about 80gsm to about 300gsm. The top coat may contain binders such as, for example, those used to prepare the size coat or primer layer, but it need not have any binders.

To facilitate good dust removal, abrasive articles according to the present disclosure may allow airflow through the abrasive article at a rate of, for example, at least 0.1L/s (e.g., at least 0.2L/s, at least 0.4L/s, at least 0.6L/s, at least 1L/s; or about 0.1L/s to about 1L/s, about 0.25L/s to about 0.75L/s, about 0.5L/s to about 1L/s, about 1L/s to about 2L/s, about 1.5L/s, or about 3L/s) such that dust may be removed from the abrasive surface by the abrasive article when in use and attached to a vacuum source (e.g., less than or equal to 40 torr (5.3 kPa)).

Objects and advantages of this disclosure are further illustrated by the following non-limiting examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this disclosure.

Examples

Objects and advantages of the present disclosure are further illustrated by the following non-limiting examples. The particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this invention. All parts, percentages, ratios, etc. in the examples and the remainder of the specification are by weight unless otherwise specified.

Example 1

A 50cm x 30cm stencil of 5 mil (127 micron) thick polyester film was prepared having a continuous wavy pattern of 3mm width, 4mm spacing, 21mm wavelength and 4.9mm amplitude. Wavy patterns were cut into the polyester film by a VLS675W CO2 laser (available from the dominant laser company of scotts, arizona). The stencil was secured on top of a release liner (commercially available as Silicone Secondary Release Liner 4999 from 3M company (3M Company,Saint Paul,Minnesota) of san Paul, minnesota) by bonding the top ends together. The chemically crosslinkable functional layer compositions were prepared by mixing the components shown in table 1 below in a black 16 oz (0.48 liter) container using a spatula at room temperature for 5 minutes.

TABLE 1

The composition was applied to the top of the stencil and forced through by hand using a polyurethane squeegee. The stencil is then removed, leaving behind a wavy patterned coating of the functional layer composition on the release liner. The patterned coating was then covered with a Mesh substrate (GR 150H 100 polyester/polyamide Mesh backing, net Mesh from sitp company (sitp, s.p.a., cene, italy)) on the non-loop side to form a laminate. The laminate was cured by: the laminate was passed through a UV processor (american ultraviolet company (american) an Ultraviolet Company, murray Hill, new Jersey)) at a time, using two V-bulbs at 400 Watts/inch in sequence ² (157.5W/cm ² ) And operating at a web speed of 30ft/min (9.1 m/min), the distance between the bulb and laminate was 2 inches (5.1 cm). The release liner is then removed to obtain a patterned coated mesh substrate.

The coating composition was prepared by mixing the components shown in table 2 with a spatula in a 16 oz (0.48 liter) container at room temperature for 5 minutes, followed by the addition of water to achieve a viscosity of about 2200 centipoise (millipascal-seconds).

TABLE 2

The coating composition was applied to the patterned coated mesh substrate via a kiss coating operation using a 2-roll coater at a speed of about 9 m/min. In the kiss coating operation, the patterned coated mesh substrate was passed through a nip between a steel top roll (pressed against the uncoated side of the patterned coated mesh substrate) and a silane rubber bottom roll of 30 shore a hardness, which was partially immersed in the coating composition in the dip pan. A doctor blade is used to remove excess coating composition from the backing roll prior to contact with the patterned coated mesh substrate. This kiss coating operation produces a primer coated mesh substrate.

An 80+ mineral blend was prepared by blending 90 wt.% P80 (grade 80 alumina mineral, available under the trade designation "BFRPL" from trichur industrial inc. Of altreholfen, treibacher Industrie AG, althofen, austria) with 10 wt.% 80+ precisely shaped particulate mineral (available as Cubitron II from 3M). The 80+ mineral blend was spread evenly on a 14 inch by 20 inch (35.6 cm by 50.8 cm) plastic mineral tray to form a mineral bed. The mineral tray is inserted onto the positive terminal of a Direct Current (DC) power supply of an electrostatic mineral coater. The primer coated mesh substrate in contact with the negative terminal of the mineral coater was suspended (with the coating surface exposed) one inch (25.4 mm) above the mineral bed. Minerals are electrostatically transferred to the coated surface by applying a Direct Current (DC) of 20 kv to 25 kv across the metal plate and the primer coated mesh substrate. The coated mesh substrate was then partially cured in a 200°f (93 ℃) oven for 30 minutes to produce an abrasive coated mesh substrate.

The abrasive coated mesh substrate is then coated again with the coating composition using the kiss coating operation described above. The coated mesh substrate was final cured in a 230°f (110 ℃) oven for 2 hours to prepare example 1.

As shown in the optical micrographs in fig. 3-6, the chemically crosslinked, patterned coated functional layer covers a portion of the openings of the mesh substrate, and the subsequent make, abrasive particles, and size coat are disposed on top of the patterned coated functional layer.

Example 2

Example 2 was prepared following the same procedure as described in example 1, except that a template of a regularly repeating square array pattern measuring 4mm wide, 4mm high, 6mm pitch was used. The chemically crosslinked, patterned coated functional layer covers a portion of the openings of the mesh substrate such that subsequent make, abrasive particles, and size are disposed on top of the patterned coated functional layer.

All cited references, patents and patent applications in the above-identified applications for patent certificates are incorporated herein by reference in their entirety in a consistent manner. In the event of an inconsistency or contradiction between the incorporated references and the present application, the information in the foregoing description shall prevail. The previous description of the disclosure, provided to enable one of ordinary skill in the art to practice the disclosure, is not to be construed as limiting the scope of the disclosure, which is defined by the appended claims and all equivalents thereof.

Claims (13)

1. An abrasive article, comprising:

a porous substrate having openings extending therethrough between opposed first and second major surfaces;

an abrasive coating disposed on only a portion of the first major surface of the porous substrate, wherein the abrasive coating comprises:

a functional layer disposed on only a portion of the first major surface of the porous substrate, wherein the functional layer comprises a first chemically cross-linked binder, wherein the functional layer completely blocks a first portion of the openings and does not completely block a second portion of the openings;

a primer layer disposed on at least a portion of the functional layer opposite the porous substrate, wherein the primer layer comprises a second chemically crosslinked binder composition; and

abrasive particles dispersed in the make coat or at least partially embedded in the make coat,

wherein the second portion of the opening allows the abraded dust to pass through the abrasive article.

2. The abrasive article of claim 1, wherein the porous substrate comprises a mesh woven fabric.

3. The abrasive article of claim 1, wherein the porous substrate comprises a knitted fabric having a volumetric porosity of at least 20%.

4. The abrasive article of claim 1, wherein the porous substrate comprises a wire mesh screen.

5. The abrasive article of claim 1, wherein the porous substrate comprises a perforated polymeric film.

6. The abrasive article of claim 1 wherein the first crosslinked bond composition comprises a crosslinked acrylic polymer.

7. The abrasive article of claim 1, wherein the second crosslinked bond composition comprises a phenolic resin.

8. The abrasive article of claim 1, wherein the abrasive particles are partially embedded in the make layer, and further comprising a size layer disposed on at least a portion of the make layer, wherein the size layer comprises a third crosslinked binder composition.

9. The abrasive article of claim 8, wherein the third crosslinked bond composition comprises a phenolic resin.

10. The abrasive article of claim 1, further comprising one component of a two-piece hook and loop attachment system secured to the porous substrate opposite the functional layer.

11. The abrasive article of claim 1, wherein the functional layer is non-contiguous.

12. A method of making an abrasive article, the method comprising:

providing a porous substrate having openings extending therethrough between opposed first and second major surfaces;

disposing a cross-linkable functional layer precursor on the first major surface of the porous substrate, wherein the cross-linkable functional layer precursor completely blocks a first portion of the openings and does not completely block a second portion of the openings;

crosslinking the crosslinkable functional layer precursor to provide a crosslinked functional layer;

disposing a curable make coat precursor on at least a portion of the crosslinked functional layer opposite the porous substrate, wherein the curable make coat precursor has abrasive particles dispersed therein;

and at least partially curing the first curable binder composition, wherein the second portion of the opening allows the abraded dust to pass through the abrasive article.

13. A method of making an abrasive article, the method comprising:

providing a porous substrate having openings extending therethrough between opposed first and second major surfaces;

Disposing a cross-linkable functional layer precursor on the first major surface of the porous substrate, wherein the cross-linkable functional layer precursor completely blocks a first portion of the openings and does not completely block a second portion of the openings;

crosslinking the crosslinkable functional layer precursor to provide a crosslinked functional layer;

disposing a curable primer layer precursor on at least a portion of the crosslinked functional layer opposite the porous substrate;

partially embedding abrasive particles in the curable make coat precursor;

at least partially curing the curable primer layer precursor to provide a primer layer;

disposing a curable size coat precursor over the make coat and at least a portion of the abrasive particles; and

at least partially curing the curable size coat precursor to provide the abrasive article, wherein the second portion of the opening allows the abraded dust to pass through the abrasive article.

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